[Federal Register Volume 77, Number 94 (Tuesday, May 15, 2012)]
[Proposed Rules]
[Pages 28533-28536]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-11697]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2012-0499; Notice No. 25-12-01-SC]
Special Conditions: Boeing, Model 737-800; Large Non-Structural
Glass in the Passenger Compartment
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
-----------------------------------------------------------------------
SUMMARY: This action proposes special conditions for the Boeing Model
737-800 airplane. This airplane as modified by Lufthansa Technik will
have a novel or unusual design feature associated with the installation
of large non-structural glass items in the cabin area of an executive
interior occupied by passengers and crew. The installation of these
items in a passenger compartment, which can be occupied during taxi,
takeoff, and landing, is a novel or unusual design feature with respect
to the material used. The applicable airworthiness regulations do not
contain adequate or appropriate safety standards for this design
feature. These proposed special conditions contain the additional
safety standards that the Administrator considers necessary to
establish a level of safety equivalent to that established by the
existing airworthiness standards.
DATES: Send your comments on or before June 4, 2012.
ADDRESSES: Send comments identified by docket number FAA-2012-0499
using any of the following methods:
Federal eRegulations Portal: Go to http://www.regulations.gov/ and follow the online instructions for sending
your comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
Hand Delivery or Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE., Washington, DC, between 8 a.m. and 5 p.m.,
Monday through Friday, except federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: The FAA will post all comments it receives, without
change, to http://www.regulations.gov/, including any personal
information the commenter provides. Using the search function of the
docket Web site, anyone can find and read the electronic form of all
comments received into any FAA docket, including the name of the
individual sending the comment (or signing the comment for an
association, business, labor union, etc.). DOT's complete Privacy Act
Statement can be found in the Federal Register published on April 11,
2000 (65 FR 19477-19478), as well as at http://DocketsInfo.dot.gov/.
Docket: Background documents or comments received may be read at
http://www.regulations.gov/ at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE.,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except federal holidays.
[[Page 28534]]
FOR FURTHER INFORMATION CONTACT: John Shelden, FAA, Cabin Safety
Branch, ANM-115, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone
425-227-2785; facsimile 425-227-1232.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite interested people to take part in this rulemaking by
sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data.
We will consider all comments we receive on or before the closing
date for comments. We may change these special conditions based on the
comments we receive.
Background
On December 16, 2010, Lufthansa Technik AG, Weg Beim Jaeger 193,
22335 Hamburg Germany applied for a supplemental type certificate for
the installation of large non-structural glass items in the cabin area
of the executive interior occupied by passengers and crew in a Boeing
Model 737-800. The Boeing Model 737-800, approved under Type
Certificate No. A16WE, is a large transport category airplane that is
limited to 189 passengers or less, depending on the interior
configuration. This specific Boeing Model 737-800 configuration
includes seating provisions for 34 passengers.
Type Certification Basis
Under the provisions of Title 14, Code of the Federal Regulations
(14 CFR) 21.101, Lufthansa Technik must show that the Boeing Model 737-
800, as changed, continues to meet the applicable provisions of the
regulations incorporated by reference in Type Certificate No. A16WE or
the applicable regulations in effect on the date of application for the
change. The regulations incorporated by reference in the type
certificate are commonly referred to as the ``original type
certification basis.'' The regulations incorporated by reference in
Type Certificate No. A16WE are as follows: 14 CFR part 25 as amended by
Amendments 25-1 through 25-77 with exceptions for the Boeing Model 737-
800. In addition, the certification basis includes certain special
conditions, exemptions, or later amended sections of the applicable
part that are not relevant to these proposed special conditions.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 25) do not contain adequate or
appropriate safety standards for the Boeing Model 737-800 because of a
novel or unusual design feature, special conditions are prescribed
under the provisions of Sec. 21.16.
Special conditions are initially applicable to the model for which
they are issued. Should the applicant apply for a supplemental type
certificate to modify any other model included on the same type
certificate to incorporate the same or similar novel or unusual design
feature, the special conditions would also apply to the other model
under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Boeing Model 737-800 must comply with the fuel vent and
exhaust emission requirements of 14 CFR part 34 and the noise
certification requirements of 14 CFR part 36.
The FAA issues special conditions, as defined in 14 CFR 11.19, in
accordance with Sec. 11.38, and they become part of the type-
certification basis under Sec. 21.101.
Novel or Unusual Design Features
The Boeing Model 737-800 will incorporate the following novel or
unusual design features: The installation of large non-structural glass
items, typically in the form of glass sheets in the cabin area of an
executive interior occupied by passengers and crew.
These installations would be for aesthetic purposes, not for
safety, in components other than windshields or windows. For these
special conditions, a large glass item is 4 kg (approximately 10
pounds) and greater in mass. This limit was established as the mass at
which a glass component could be expected to potentially cause
widespread injury if it were to shatter or break free from its
retention system.
The proposed special conditions address the novel and unusual
design features for the use of large non-structural glass in the
passenger cabin. These large glass items would be installed in occupied
rooms or areas during taxi, take off, and landing, or rooms or areas
that occupants do have to enter or pass through to get to any emergency
exit. The installations of large non-structural glass items may
include, but are not limited to, the following items:
Glass partitions.
Glass attached to the ceiling.
Wall/door mounted mirrors/glass panels.
Discussion
The existing part 25 regulations only address the use of glass in
windshields, instrument or display transparencies, or window
applications. The regulations treat glass as unique for special
applications where no other material will serve and address the adverse
properties of glass.
Section 25.775, ``Window and windshields,'' provides for the use of
glass in airplanes but limits glass to windshields and instrument or
display transparencies. Furthermore, except for bolted-in windshields,
there is limited experience with either adhesive or mechanical
retention methods for large glass objects installed in an airplane
subject to high loads supported by flexible restraints.
The FAA has accepted the following uses of glass in the passenger
cabin under the current regulations:
1. Glass items installed in rooms or areas in the cabin that are
not occupied during taxi, take off, and landing, and occupants do not
have to enter or pass through the room or area to get to any emergency
exit.
2. Glass items integrated into a functional device whose operation
is dependent upon the characteristics of glass, such as instrument or
indicator protective transparencies, or monitor screens such as liquid
crystal display (LCD) or plasma displays. These glass items may be
installed in any area in the cabin regardless of occupancy during taxi,
take-off, and landing. Acceptable means for these items may depend on
the size and specific location of the device.
3. Small glass items installed in occupied rooms or areas during
taxi, take off, and landing, or rooms or areas that occupants do have
to enter or pass through to get to any emergency exit. For the purposes
of these special conditions, a small glass item is less than 4 kg in
mass or a group of glass items weighing less than 4 kg in mass.
The glass items in numbers one, two, and three (above) have been
restricted to applications where the potential for injury is either
highly localized (such as instrument faces) or the location is such
that injury due to failure of the glass is unlikely (e.g., mirrors in
lavatories). These glass items are subject to the inertia loads
contained in Sec. 25.561 and maximum positive differential pressure
for items like monitors, but are not subject to these special
conditions. They have been found acceptable through project specific
means of compliance requiring testing to meet the requirement in Sec.
25.785(d) and by adding a protective polycarbonate layer
[[Page 28535]]
that covers the glass exposed to the cabin.
The use of glass in airplanes utilizes the one unique
characteristic of glass--its capability for undistorted or controlled
light transmittance, or transparency. Glass, in its basic form as
annealed, untreated sheet, plate, or float glass, when compared to
metals, is extremely notch-sensitive, has a low fracture resistance,
has a low modulus of elasticity, and can be highly variable in its
properties. While reasonably strong, it is not a desirable material for
traditional aircraft applications because, as a solo component, it is
heavy (about the same density as aluminum). In addition, when glass
fails, it can break into extremely sharp fragments that have the
potential for injury above and beyond simple impact and have been known
to be lethal.
The proposed special conditions address installing glass in much
larger sizes than previously accepted and in a multitude of locations
and applications, instead of using more traditional aircraft materials.
In most, if not all cases, the glass will not be covered with a
polycarbonate layer. Additionally, the retention of glass of this size
and weight is not amenable to conventional techniques currently
utilized in airplane cabins.
The proposed special conditions consider the unusual material
properties of glass as an interior material that have limited or
prevented its use in the past, and address the performance standards
needed to ensure that those properties do not reduce the level of
safety intended by the regulations. They address the use of large glass
items installed in occupied rooms or areas during taxi, take off, and
landing, or rooms or areas that occupants do have to enter or pass
through to get to any emergency exit.
The proposed special conditions define a large glass component
threshold of 4 kg, which is based on an assessment of the mass
dislodged during a high ``g'' level (as defined in Sec. 25.562) event.
Groupings of glass components that total more than 4 kg would also need
to be included. The applicable performance standards in the regulations
for the installation of these components also apply and should not
adversely affect the standards provided below. For example, heat
release and smoke density testing should not result in fragmentation of
the component.
For large glass components mounted in a cabin occupied by
passengers or crew that are not otherwise protected from the injurious
effects of failure of the glass component, the following apply:
Material. The glass used must be tempered or otherwise treated to
ensure that when fractured, it breaks into small pieces with relatively
dull edges. This must be demonstrated by testing to failure. Tests
similar to ANSI/SAE Z26.1 section 5.7, Test 7 would be acceptable.
Fragmentation. The glass component construction must control the
fragmentation of the glass to minimize the danger from flying glass
shards or pieces. Impact and puncture testing to failure must
demonstrate this. Tests similar to ANSI/SAE Z26.1 section 5.9, Test 9
adjusted to ensure cracking the glass would be acceptable.
Strength. The glass component, as installed in the airplane, must
be strong enough to meet the load requirements for all flight and
landing loads and all of the emergency landing conditions in subparts C
and D of part 25. In addition, glass components that are located such
that they are not protected from contact with cabin occupants must be
designed for abusive loading without failure, such as impact from
service carts, or occupants stumbling into, leaning against, sitting
on, or performing other intentional or unintentional forceful contact.
This must be demonstrated by static structural testing to ultimate load
except that the critical loading condition must be tested to failure.
The tested glass component must have all features that affect component
strength, such as etched surfaces, cut or engraved designs, holes, and
so forth.
Retention. The glass component, as installed in the airplane, must
not come free of its restraint or mounting system in the event of an
emergency landing. Based on the characteristics of a large glass
component, dynamic tests should be performed to demonstrate that the
occupants would be protected up to the load levels required by the
certification basis of the airplane. A single test for the most
critical loading for the installed component would be sufficient. This
may be accomplished by using already accepted methods for dynamic
testing.
Analysis may be used in lieu of testing if the applicant has
validated the strength models and dynamic simulation models used
against static tests to failure and dynamic testing to the above
requirements and can predict structural failure and dynamic response
and inertial load. The glass material properties must meet Sec.
25.613, ``Material strength properties and material design values.''
The effect of design details, such as geometric discontinuities or
surface finish, must be accounted for in the test/analysis.
Applicability
As discussed above, these special conditions are applicable to the
Boeing Model 737-800. Should Lufthansa Technik apply at a later date
for a supplemental type certificate to modify any other model included
on Type Certificate No. A16WE to incorporate the same novel or unusual
design feature, the special conditions would apply to that model as
well.
Certification of the Boeing Model 737-800 is currently scheduled
for June 2012. The substance of these special conditions has been
previously subject to the notice and public-comment procedure.
Therefore, because a delay would significantly affect both the
applicant's installation of the system and certification of the
airplane, we are shortening the public-comment period to 20 days.
Conclusion
This action affects only certain novel or unusual design features
on one model of airplanes. It is not a rule of general applicability,
and it affects only the applicant who applied to the FAA for approval
of these features on the airplane.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Boeing Model 737-800 airplanes modified by Lufthansa Technik AG.
For these special conditions, a large glass component is 4 kg
(approximately 10 pounds) and greater in mass, or a grouping of glass
components that total more than 4 kg.
1. Boeing Model 737-800 Airplane; Large Non-Structural Glass in the
Passenger Compartment. The airplane is not operated for hire or offered
for common carriage. This provision does not preclude the operator from
receiving remuneration to the extent consistent with 14 CFR parts 125
and 91, subpart F, as applicable.
2. Material Fragmentation. The glass used to fabricate the
component must be tempered or treated to ensure that, when fractured,
it breaks into small pieces with relatively dull edges. In addition, it
must be shown that fragmentation of the glass is controlled to reduce
the danger from flying glass shards or
[[Page 28536]]
pieces. This must be demonstrated by testing to failure.
3. Component Strength. The glass component must be strong enough to
meet the load requirements for all flight and landing loads including
any of the applicable emergency landing conditions in subparts C and D
of part 25. Abuse loading without failure, such as impact from
occupants stumbling into, leaning against, sitting on, or performing
other intentional or unintentional forceful contact, must also be
demonstrated. This must be demonstrated by static structural testing to
ultimate load, except that the critical loading condition must be
tested to failure in the as-installed condition. The tested glass must
have all features that affect component strength, such as etched
surfaces, cut or engraved designs, holes, and so forth. Glass pieces
must be non-hazardous.
4. Component Retention. The glass component, as installed in the
airplane, must not come free of its restraint or mounting system in the
event of an emergency landing. A test must be performed to demonstrate
that the occupants would be protected from the effects of the component
failing or becoming free of restraint under dynamic loading. The
dynamic loading of Sec. 25.562(b)(2) is considered an acceptable
dynamic event. The applicant may propose an alternate pulse; however,
the impulse and peak load may not be less than that of Sec.
25.562(b)(2). As an alternative to a dynamic test, static testing may
be used if the loading is assessed as equivalent as or more critical
than a dynamic test, based upon validated dynamic analysis. Both the
primary directional loading and rebound conditions need to be assessed.
5. Instructions for Continued Airworthiness. The instructions for
continued airworthiness will reflect the fastening method used and will
ensure the reliability of the methods used (e.g., life limit of
adhesives, or clamp connection). Inspection methods and intervals will
be defined based upon adhesion data from the manufacturer of the
adhesive or actual adhesion test data, if necessary.
Issued in Renton, Washington, on May 1, 2012.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2012-11697 Filed 5-14-12; 8:45 am]
BILLING CODE 4910-13-P